In typical computer systems, configuration of various system components is fixed. In a typical prior art static configuration scheme for a computing system, as shown in FIG. 1, a central processing unit (CPU) 50 is coupled to peripheral devices 51, 52, 53, and 54. Each device of peripheral devices 51-54 may be, for example, a memory device such as a random access memory (RAM) or a read only memory (ROM), or a non-memory device such as a display, printer, or communication controller, Peripheral devices 51-54 are coupled to CPU 50 through a bus 65. Each of peripheral devices 51-54 has assigned to it a fixed address. CPU 50 may independently interact with each of peripheral devices 51-54 by utilizing its fixed address. Peripheral devices 51-54 are each coupled to an associated address compare register 61-64 and an address select circuit 71-74. When CPU 50 or another device sends an instruction on bus 65, address compare registers 61-64 and address select circuits 71-74 screen the instruction so that each of the peripheral devices 51-54 responds only to instruction which include the fixed address assigned to that peripheral device.
The use of static configuration schemes, as that described above, inherently limits flexibility. Adding or removing devices becomes difficult, as some physical change in the system is required to allow a new device to be accessed or to indicate that a removed device is no longer present.